Granular filtration media mixture and uses in water purification

ABSTRACT

Provided is a granular filtration media comprising a mixture of granular filtration media and less than 2.5% of nanofibers based on the dry weight, method of making the same and uses of the same for removing contaminants from water, including metals, heavy metals, synthetic or natural organic matters, colloidal or suspended particles to improve the chemical safety and purity of water for the purpose of water purification, specifically, one embodiment of the present invention disclosed is use of the granular filtration media to remove particulate lead from high pH water.

CROSS-REFERENCE(S) TO RELATED APPLICATION(S)

This application is a Continuation-in-Part of U.S. application Ser. No.15/503,999, filed Feb. 14, 2017, which is a U.S. National Stage ofInternational Application No. PCT/US2015/045339, filed Aug. 14, 2015,which claims the benefit of U.S. Provisional Application No. 62/038,068,filed on Aug. 15, 2014; U.S. Provisional Application No. 62/117,932,filed on Feb. 18, 2015; and U.S. Provisional Application No. 62/203,294filed on Aug. 10, 2015, the disclosures of which are expresslyincorporated herein by reference.

TECHNICAL FIELD

Embodiments of this invention relate to a composite granular filtrationmedia comprising a mixture of granular filtration media and nanofibersto remove contaminants from water source such as drinking water forwater purification application.

BACKGROUND

Safe and clean drinking-water is a basic need for human development,health, and well-being. As global industrialization and economicdevelopment continue growing, the concerns associated with watercontamination are becoming more serious and urgent to be addressed. Theincreasing consumption of contaminated water for human is also arisingmore and more health-related public concerns. Therefore, the need forimproving water purification technology continues to grow dramaticallyin the U. S. and abroad.

Generally, the contaminants in the water can be categorized intochemical contaminants and biological contaminants. As water pollution isincreasing in occurrence, the potential health and safety issuesassociated with the chemical contaminants in the water is becoming amore prominent global concern. Some examples of the chemicalcontaminants include toxic anions (fluoride, arsenite, arsenate,nitrate, chromate, selenite, selenate, etc.); metals; heavy metals(lead, mercury, cadmium, zinc, copper, chromium, etc.); synthetic ornatural organic matters; etc. It is well known that most of the heavymetals are toxic to human beings and should be removed from drinkingwater.

Additionally, many water treatment applications are required to meetspecific regulatory requirements pertaining to the removal of thesespecies prior to discharge. These regulations are subject to change as aresult of scientific findings as well as with improveddetection/analytical techniques. For example, in 2007, the NSF Intl.Drinking Water Treatment Unit Joint Committee revised the NSF/ANSIStandard 53 protocol for pH 8.5 lead reduction based on research intothe nature of lead particles. The new protocol specifies a size rangefor the colloidal or fine particle portion (between 0.1-1.2 micron)which was undefined previously. This change did not pose a significantproblem for pressurized filters (e.g. carbon blocks) but did introduceadditional challenges for low pressure (less than 30 psi) and gravityflow filters, which have difficulty with colloidal materials

Gravity flow or low pressure flow filtration systems are well known inthe art, because of their generally lower cost and user convenience.Such systems include pour-through carafes, water coolers andrefrigerator water tanks, which have been developed by The CloroxCompany®, Culligan®, Rubbermaid®, and Glacier Pure®, et al. Typically,these systems are filled with tap water from municipal supplies or ruralwells, as the user wishes to remove chlorine and/or lead or otherchemical contaminants, or to generally improve the chemical safety ofthe water and the taste/odor of the water. The marketing need of thesedevices is continuing to grow quickly, especially in view of theemphasis on healthier and safer drinking water, and further in view ofthe expense and inconvenience of purchasing bottled water.

Most of the gravity-fed or low pressure flow filters utilize acombination of granular filtration media, such as granular-activatedcarbon (GAC) and ion exchange resin (IER). These devices have beenproven effective in removing contaminants such as organics, copper,mercury, cadmium, zinc, and residual chlorine, etc., within complianceof regulatory standards. Commercially, these filtration devicestypically feature relatively small, disposable and replaceable filtercartridges that are inserted into the water purification devices andused for several weeks of normal use. However, one problem associatedwith filters containing a mixture of granular activated carbon and ionexchange resin is that they have limited contaminant removal capability.When large granules are packed together, large interstitial voids canform between the granules, which results in effective pore sizes whichare larger than colloidal particles. These particles, like the onesspecified by the NSF/ANSI 53 protocol, could pass through these voidsand into the effluent, thus may fail to meet regulatory standards.

Granular activated carbon, with or without binder, and with or withoutvarious other additives such as lead scavengers, has been well developedand broadly used as a filtration media in water purification filters formany years. The granular activated carbon is typically loaded into acompartment inside a filter housing to act as a filter or a carbon“bed”. The housing and internals are designed to contain the loosegranules in place in the compartment, to distribute water to the inletof the bed, and collect the water at the outlet of the bed. Generally, abed of GAC, with optional other granular media or additives, is thetypical media composition of choice for low pressure or gravity flowapplications, because of the relatively low pressure drop through thebed of granules than other media.

Good water flow rate through the filter is another primary concern in alow pressure or a gravity flow water system such as a water pitcherdevice, water cooler device, or the like because this affects howquickly filtered water from a freshly-water-filled device may be used tosatisfy the consumer's expectation. That is why the granular filtrationmedia mixture is frequently selected to fill in those types of filters.

Overall, the ideal filter for the gravity-fed or low pressure deviceprovides high efficiency at contaminant removal and high flow rate. Theexisting gravity flow or low pressure flow filters can generally achievea good flow rate, however, as mentioned previously, they also have somelimited contaminant removal capability to removal particulatecontaminants from the water source. Therefore, the existing gravity flowand low pressure flow granular filtration media mixture needs to beimproved to achieve higher contaminant removal efficacy, specificallywith regards to colloidal and suspended particles.

Knipmeyer, in U.S. Pat. No. 8,167,141, discloses a gravity-fed carbonblock water filter comprising an activated carbon and a lead scavenger,which could deliver a final effluent water containing less than 10 ppbafter 151 liters of source water filtration to meet the revised NSFstandard of lead removal claim. However, when carbon blocks designed forpressurized systems are applied to gravity flow systems, they often addmore cost and fail to produce the desired flow rates consistently overtime.

U.S. Pat. No. 8,002,990, issued to Schroeder on Aug. 23, 2011, disclosesa filter using fibrillated nanofiber-loaded fine powders of filtermedia, such as ion exchange resin, to remove soluble and insolubleparticles from a fluid. However, when the media is used in a gravity-fedor a low pressure filtration system, the flow rate will be significantlyreduced in comparison with the granular filtration media. Furthermore,compared with the present commercially available gravity-fed or lowpressure-fed filters filled with granular filtration media the cost willalso be more greater.

Koslow, in U.S. Pat. Nos. 6,872,311; 6,913,154, discloses the use ofnanofibers to improve filtration efficiency. These patents teach afibrillated physical process that can enhance the performance ofexisting standard filter media such as cellulose fiber, and furtherteach a method of making an improved air filter medium incorporated withnanofibers. However, this invention does not teach how to improve theexisting granular filtration media for the purpose of removal ofparticulates from a contaminated water by using nanofibers.

Halbfoster, in U.S. Pat. No. 4,190,532, describes a filter materialcomposition comprising a mixture of ion exchange resin particles andcellulose filter aid for use in removing suspended and colloidalparticles, such as silica or iron oxide, from water. This invention hasbeen commercially practiced in the high quality water supply process fora long time, however the particle removal efficacy still needs to beimproved.

It is believed that there is a need to improve existing granular media(and combinations) for use in gravity flow and low pressure filters suchthat adequate flow rates are achieved while maintaining high contaminantremoval. Specifically, there is a need for media that can removecolloidal and suspended particles from water, such as particulate leadas specified in NSF/ANSI 53.

SUMMARY OF THE INVENTION

Provided is a granular filtration media mixture comprising granularfiltration media and less than 5%, less than 4.5%, less than 4.0%, lessthan 3.5%, less than 3.0%, less than 2.5%, less than 2.0%, less than1.5%, or less than 1.0% of nanofibers based on the dry weight, andoptionally, further having a moisture content in a range of 3% to 70% byweight.

In one embodiment, a granular filtration media includes but not limitedto, porous or nonporous, dry or moisture-containing granular particleshaving the particle size in the range of 100-2000 microns.

In another embodiment, the nanofiber includes but not limited to,synthetic polymeric nanofiber, natural polymeric nanofiber, andderivative of natural polymeric nanofiber, inorganic nanofiber or anycombinations of thereof, and further having an average diameter in arange of 5 nanometers to 2 microns.

In an additional embodiment of the present invention, provides a methodof preparing a granular filtration media mixture comprising the stepsof:

1) Dispersing the nanofiber in a solvent composition to prepare ananofiber dispersion.

2) Adding granular filtration media into the nanofiber dispersion andblend them together and separating them by filtration. The finalgranular media product could be used as it is or further to be dried tomoisture content not less than 3%.

In another embodiment, provides a method of use of the granularfiltration media mixture provided by this invention to removecontaminants from water (e.g. drinking water, industrial water,environmental water, recreational water) by contacting the water withthe granular filtration media mixture with or without combinations ofother filtration media for the purpose of water purificationapplications.

In one embodiment of the present invention, provides a water filtercomprising of the granular filtration media mixture alone orcombinations of other existing filtration media, it may be used in a tapwater from municipal supplies or rural wells; point-of-use;point-of-entry; municipal water treatment; recreational water from apool or spa; environmental water; industrial process water; industrialwaste water; municipal waste water and agriculture irrigation water toremove contaminants, such as particulate particles, colloidal particles,fine particles, suspended particles, organic, residual halogen,selenium, metals, heavy metals (lead, copper, mercury, cadmium, zinc,chromium), etc.

In one embodiment, a granular filtration media mixture includes agranular filtration media and nanofibers, wherein the granularfiltration media has an average particles size in the range of 100micron to 2000 microns, and the nanofibers have an average diameter in arange of 5 nanometers to 2.0 microns.

In one embodiment, a granular filtration media mixture includes agranular filtration media and nanofibers in an amount of less than 5%,less than 4.5%, less than 4.0%, less than 3.5%, less than 3.0%, lessthan 2.5%, less than 2.0%, less than 1.5%, or less than 1.0% by dryweight of said filtration medium.

In one embodiment, a granular filtration media mixture includes agranular filtration media and fibrillated nanofibers, wherein themixture has a moisture content in the range of 3% to 70%.

In one embodiment, a granular filtration media mixture includes agranular filtration media and nanofibers, wherein the granularfiltration media has an average particle size in a range of 100 micronto 2000 microns and is selected from the group of granular activatedcarbon, granular activated alumina, granular diatomaceous earth,granular silica gel, granular zeolites, granular silicates, granularsynthetic molecular sieves, granular ion exchange resin particles,granular mineral clay, granular aluminosilicates, granular titanates,granular bone char, granular KDF process media, granular iodated resins,granular ceramic, granular perlite, granular sand, granular hybrid ofion exchange resin with metal oxides, granular hybrid of activatedcarbon with metal oxides, functionalized granular activated carbon,polymeric adsorbent resins, or any combinations thereof. Wherein said ananofiber having an average diameter in a range of 5 nanometers to 2.0microns, is selected from synthetic polymeric nanofiber, naturalpolymeric nanofiber, derivative of natural polymeric nanofiber,inorganic nanofiber or any combinations of thereof.

In one embodiment, a method of making the granular filtration mediamixture includes the steps of: dispersing nanofibers; and addinggranular filtration media into the nanofiber dispersion; and mixing; andseparating by filtration; and obtaining a wet media or dry media bydrying.

In one embodiment, a method of enhancing performance of a granularfiltration media-containing filter includes the step of:

Providing a fibrillated nanofiber dispersion; wet laying or placing thedispersion onto the top surface of filtration media of the filter,wherein the total amount of the fibrillated nanofibers is less than 5%,less than 4.5%, less than 4.0%, less than 3.5%, less than 3.0%, lessthan 2.5%, less than 2.0%, less than 1.5%, or less than 1.0% by dryweight of the total granular filtration media of the filter.

In one embodiment, a granular filtration medium comprising the mixtureof a granular filtration medium and fibrillated nanofibers is used inremoving impurities from a fluid system.

In one embodiment, the fluid system to be purified is water. In oneembodiment, the fluid system to be purified is air.

In one embodiment, the impurities to be removed from the water or airfluid systems are selected from the group of residual halogen, heavymetal ions, colloidal particles, fine particles, organic contaminants,or any combination thereof.

In one embodiment, the impurities to be removed from the water or airfluid systems are particulate lead.

In one embodiment, the impurities to be removed from the water or airfluid systems are selected from colloidal and fine particles of lead,copper, iron oxide, iron oxide hydroxide, and silica.

In one embodiment, the impurities to be removed from the water or airfluid systems are selected from the group of copper, mercury, lead,cadmium, and zinc.

In one embodiment, the impurities to be removed from the water or airfluid systems are total available residual halogen (e.g. chlorine orbromine) in the water.

In one embodiment, a water purification filter includes a first granularfiltration medium, a screen separator, and a filtration medium mixtureof granular filtration medium and nanofibers.

In one embodiment, a water purification filter including the firstgranular filtration medium, the screen separator, and the filtrationmedium mixture of granular filtration medium and nanofibers is used in agravity-fed and or a low pressure-fed filtration system to removecopper, zinc, mercury, cadmium, lead in a gravity-fed or lowpressure-fed filter to meet the NSF 42/53 compliance.

In one embodiment, a water purification filter includes a mixture offiltration medium comprising of granular activated carbon, ion exchangeresins and fibrillated nanofibers.

In one embodiment, a water purification filter including the mixture offiltration medium comprising of granular activated carbon, ion exchangeresins and fibrillated nanofibers is used in a gravity-fed and or a lowpressure-fed filtration system to remove water contaminants includingbut not limited to residual halogen, copper, zinc, cadmium, mercury,lead, organic contaminants.

In one embodiment, a water purification filter includes a wet laidfibrillated nanofiber dispersion on the top of a filtration mediummixture of granular activated carbon and ion exchange resins.

In one embodiment, a water purification filter including the wet laidfibrillated nanofiber dispersion on the top of the filtration mediummixture of granular activated carbon and ion exchange resins is used ina gravity-fed and or a low pressure-fed filtration system to removewater contaminants including but not limited to residual halogen,copper, zinc, cadmium, mercury, lead, organic.

In one embodiment, a method of purifying water includes:

Allow contaminated water flow through a filter comprised of mixedgranular filtration media with fibrillated nanofibers followed by flowthrough a filter comprised of ion exchange resin to remove watercontaminants including but not limited to residual halogen, copper,zinc, cadmium, mercury, lead, organic.

In one embodiment, a method of making a water purification filterincludes:

First placing a granular filtration medium in the bottom of a filterchamber or a bed, followed by placing a screen separator, a mixedgranular filtration medium with fibrillated nanofibers on the top, andsealed.

In one embodiment, a method of making a water purification filterincludes filling the mixed filtration medium of granular activatedcarbon, ion exchange resins and fibrillated nanofibers in a filtercartridge and or filter beds.

In one embodiment, a method of making a water purification filterincludes first filling a filter cartridge with a mixture of granularfiltration medium and followed by wet laid a fibrillated nanofiberdispersion on the top of the filter.

In one embodiment, a method of making a water purification filterincludes first placing a granular filtration medium in the bottom offilter cartridge, followed by placing a screen on the top of the firstfiltration medium, then placing the mixed filtration media of multiplegranular filtration media and fibrillated nanofibers.

In one embodiment, a water purification filter includes a first mediamixture comprising of granular filtration media and nanofibers; and asecond granular filtration media, with or without a screen to separatethe first media and the second media, or just blend the first and secondmedia together.

In one embodiment, the first media mixture is selected from combinationsof nanofibers admixed with any combinations of activated carbonparticles, zeolite, ion exchange resin, or silica; and the secondfiltration media is selected from ion exchange resin, zeolite.

In one embodiment, the water filter including the first media mixturecomprising of granular filtration media and nanofibers and the secondgranular filtration media can be used in a gravity flow and or a lowpressure flow cartridge, to remove chemical contaminants includingwithout being limited to, organic matters, copper, zinc, mercury,cadmium, lead, residual halogen such as residual chlorine or residualbromine in the drinking water source.

These and other embodiments will be further appreciated with referenceto the following detailed description and examples.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic illustration of an embodiment of a filter; and

FIG. 2 is a schematic illustration of an embodiment of a filter.

DETAILED DESCRIPTION

The objective of the present invention is to provide a granularfiltration media mixture composition comprising of granular filtrationmedia and nanofibers, and the uses of the same to improve the watercontaminants reduction or removal efficacy for the application of waterpurification.

It is well-known that the granular filtration media in the prior art hasbeen broadly used in the water purification not only for the benefits ofhigh flow rate, also for convenience and cost-effectiveness, however,the removal efficacy for the particulate particles from the water needsto be improved.

Definitions

The term “impurities or contaminants from water” shall mean chemicalcontaminants and or biological contaminants. The biological contaminantshave been addressed by disinfection technology. The chemicalcontaminants will include without being limited to: particulateparticles, colloidal particles, fine particles, suspended particles,organic compounds, residual halogen, selenium, arsenate, arsenite,fluoride, dichromate, manganese, tin, platinum, iron, cobalt, chromate,molybdate, selenite, senelate, uranium, vanadium, vanadate, ruthenium,antimony, molybdenum, tungsten, barium, cerium, lanthanum, zirconium,titanium, and or radium, zinc, copper, lead, mercury, cadmium, as wellas natural organic matter (NOM), pesticide and herbicide residues,endocrine disruptors, pharmaceutical residues and organic compoundsreleased through industrial discharges. For example, most of the heavymetals are toxic to human beings and should be removed by a filtrationor a purification process.

The terms “particles and particulates” are being used substantiallyinterchangeable. Generally, a particle is a small piece or individualpart. A particulate pertains to or is formed of particles. The particlesused in embodiments of the present invention can remain separate or mayclump, physically intermesh, electro-statically associate, or otherwiseassociate to form particulates. The particulate can include suspendedparticles, colloidal particles, or fine particles within a range ofparticle size 50 nm to 100 microns.

The term “colloidal or fine particles”, as used herein, refers to aportion of particulate particles with a size range of 50 nanometers to 2microns (1 micron is 0.001 millimeter) in the water, for example, theNSF defines the fine particulate portion of lead particle size between0.1 to 1.2 microns in water.

The term “suspended particles” refers to particulate size larger than 2microns.

The term “gravity-fed or gravity-flow” filtration refers to the flow ofa fluid through a filtration media wherein gravity is substantially theonly motive force acting upon the fluid to force the fluid through thefiltration media.

The term “low pressure flow” filtration refers to the flow of a fluidthrough a filtration media wherein the pressure of fluid within 30 psior less is the motive force to move the fluid through the filtrationmedia.

The term “nanofiber” or “nanofibers” refers to a fiber having a diameteror average diameter less than about 2.0 microns. In a preferredembodiment, the diameter or average diameter of nanofibers is less than1000 nanometers.

The term “dispersion of nanofibers” shall mean a nanofiber or nanofibersare dispersed in a solvent comprising of a water, an aqueous, an organicsolvent or any combination therein, the total nanofibers in a dispersionis not more than 10% by dry weight, preferably, not more than 5%.

The term “granular filtration media” (GFM) shall mean the porous and ornonporous, dry or moisture-containing granular filtration mediaparticles having the particle size or average particle size in the rangeof 100-2000 microns.

In one embodiment of the present invention, provides a granularfiltration media mixture comprising of a mixture of a granularfiltration media (GFM) and less than 5%, less than 4.5%, less than 4.0%,less than 3.5%, less than 3.0%, less than 2.5%, less than 2.0%, lessthan 1.5%, or less than 1.0% of nanofibers based on the dry weight, andoptionally, the moisture content is in a range of 3% to 70% by weight.

A granular filtration media (GFM) could be porous and or nonporous, dryor moisture-containing, granular filtration media particles havingmoisture content in the range of 3%-70%, having the particle size oraverage particle size in the range of 100-2000 microns. In a preferredembodiment, the moisture content in the range of 3%-60%, particle sizeor average particle size distribution is in the range of 200-2000microns. In a most preferred embodiment of the present invention, theparticle size or average particle size distribution is in the range of300-1500 microns. Examples of granular filtration media includes withoutbeing limited to, activated carbon particles, granular activated carbon(GAC), functionalized granular activated carbon, silica gel, sand,fractured anthracite coal, ion exchange resin beads, ion exchanger-basedhybrid particles such as iron oxide hydroxide hybrid ion exchange hybriddescribed in U.S. Pat. Nos. 7,504,036; 7,291,578; 7,708,892, polymericadsorbent resins such as Amberlite™ XAD type of polymeric adsorbents,activated alumina, zeolites, clay minerals, synthetic molecular sieves,KDF process filtration media (Cu—Zn formulations), aluminosilicates,titanates, bone char, ceramic, diatomaceous earth (DE) or metaloxide-hydroxide impregnated DE (traded name-NXT-2 media furtherdescribed in U.S. Pat. No. 8,110,526), or any combinations of thereof.In a preferred embodiment, the granular filtration media is selectedfrom ion exchange resin particles; zeolites; activated carbon particles(granular activated carbon); synthetic molecular sieve particles;diatomaceous earth; silica; clay, etc.

Nanofibers include without being limited to, synthetic polymericnanofiber, natural polymeric nanofiber, derivatives of natural polymericnanofibers, inorganic nanofibers or any combinations of thereof. Thenanofiber or nanofibers refers to a fiber having a diameter or averagediameter in a range of 5 nanometers to 2.0 microns; in a preferredembodiment, having a diameter or average diameter in a range of 10 to1000 nanometers; in a most preferred embodiment, having a diameter oraverage diameter in a range of 20 to 800 nanometers, between 100 and 700nanometers, between 200 and 500 nanometers, or between 300 and 400nanometers. In an embodiment, the length of the nanofiber is between 1mm and 20 mm, between 2 mm and 10 mm, between 3 mm and 8 mm, or between4 and 6 mm. In one embodiment, the nanofibers in the granular filtrationmedia mixture is in the range of 0.01% to 5% by dry weight, preferably,in a range of 0.04-3% by dry weight. Therefore, the dry weight of thenanofibers can comprise any value or any included range between theseendpoints having greater than 0.01% and less than 5%, less than 4.9%,less than 4.8%, less than 4.7%, less than 4.6%. less than 4.5%, lessthan 4.4%, less than 4.3%, less than, 4.2%, less than 4.1%, less than4.0%, less than 3.9%, less than 3.8%, less than 3.7%, less than 3.6%.less than 3.5%, less than 3.4%, less than 3.3%, less than, 3.2%, lessthan 3.1%, less than 3.0%, less than 2.9%, less than 2.8%, less than2.7%, less than 2.6%. less than 2.5%, less than 2.4%, less than 2.3%,less than, 2.2%, less than 2.1%, less than 2.0%, less than 1.9%, lessthan 1.8%, less than 1.7%, less than 1.6%. less than 1.5%, less than1.4%, less than 1.3%, less than, 1.2%, less than 1.1%, less than 1.0%,less than 0.9%, less than 0.8%, less than 0.7%, less than 0.6%. lessthan 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than0.1% dry weight of the nanofibers.

A “granular filtration media mixture” can include one or more types ofthe granular filtration media and one or more types of the nanofibersdescribed herein.

Examples of a nanofiber for the present invention includes without beinglimited to, nano synthetic polymeric fiber, nano engineered-resin fiber,nano ceramic fiber, nanofibrillated or microfibrillated cellulose fiber,nano chitin fiber, nano chitosan fiber, derivatives of nano cellulosefiber, nano rayon fiber, nano glass fiber, nano alumina fiber, nanoaluminahydroxide fiber, nano titania fiber, nanocarbon tube, nanocarbonfiber, or nano activated carbon fiber, nano silica fiber, nano zeolitefiber, or any combination of thereof.

The nanofibers can generally be produced by interfacial polymerization,electro spinning, and forcespinning from different materials. The mostcommon process for nanofiber preparation is electrospinning, also knownas electrostatic spinning, refers to a technology which produces fibersfrom a polymer solution or polymer melt using interactions between fluiddynamics, electrically charged surfaces and electrically chargedliquids. The book “Electrospinning of Micro- and Nanofibers;Fundamentals and Applications in Separation and Filtration Processes” byY. Filatov, A. Budyka, and V. Kirichenko is devoted to the scientificand technical aspects of electrospinning process. More than 100different polymers both synthetic and natural can be electrospun intonanofibers, mostly from polymer solution, some examples includes withoutbeing limited to, polyacrylonitrile (PAN), poly(ethylene oxide) (PEO),poly(ethylene terephthalate) (PET), polystyrene (PS),poly(vinylchloride) (PVC), Nylon-6, poly(vinyl alcohol) (PVA),poly(E-caprolactone) (PCL), Kevilar [poly(p-phenylene terephthalamide),or PPTA], poly(vinylidene fluoride) (PVDF), polybenzimidazole (PBI),polyurethanes (PUs), polycarbonates, polysulfones, poly(vinyl phenol)(PVP), microfiburous cellulose, carboxymethylcellulose, polylactic acid,chitin, chitosan, collagen, gelatin, polyaniline, block copolymers asshown for the example of styrene-butadiene-styrene triblock copolymers,nano carbon fibers, electrospun titania (TiO2) nanofibers, aluminananofibers, ceramic nanofibers, et al.

In a preferred embodiment of the present invention, a nanofiber ornanofibers are selected from nano cellulose fiber, nanofibrillatedcellulose fiber (NFC), microfibrillated cellulose fiber (MFC), nanochitin fiber, nano chitosan fiber, nano collagen fiber, nano geltinfiber, derivatives of cellulose nanofibers, nano poly(vinyl alcohol)(PVA) fiber, nano polyacrylonitrile (PAN) fiber, nano carbon fibers,electrospun titania (TiO2) nanofibers, alumina nanofibers, aluminahydroxide nanofibers, ceramic nanofibers, or any combination of thereof.

In a more preferred embodiment of the present invention, a nanofiber ornanofibers are selected from nano cellulose fiber, nanofibrillatedcellulose fiber (NFC), microfibrillated cellulose fiber (MFC),derivatives of nanocellulose fiber, derivatives of cellulose nanofiber,nano chitin fiber, nano chitosan fiber, or any combination of thereof.

In the most preferred embodiment to the present invention, a nanofiberor nanofibers are selected from nanocellulose fiber, nanofibrillatedcellulose fiber (NFC), microfibrillated cellulose fiber (MFC),derivatives of nanocellulose fiber, derivatives of cellulose nanofiberor any combination of thereof. A nano cellulose fiber comprising ofnanosized cellulose fibrils with a high aspect ratio, is also referredto microfibrillated cellulose (MFC); cellulose microfibrils; fibrillatedcellulose; nanofibrillar cellulose (NFC); fibril aggregates; nanoscalecellulose fibrils; microfibrillated cellulose nanofibers; cellulosefibril aggregates; cellulose nanofibers (CNF); cellulose nanofibrils;cellulose microfibers; microfibril aggregates; cellulose microfibrilaggregates; cellulose fibrils; nanofibrillated cellulose (NFC);microfibrillar cellulose; nanowhiskers; nanocrystalline cellulose (NCC).The nanofibrillated cellulose fiber (NFC) can be prepared by methods,including homogenization of pulp fibers; grinding discs; Cryocrushing;high-intensity ultrasonication; electroospinning, etc. Its preparationand properties are also disclosed in U.S. Pat. Nos. 4,374,702;4,483,743; 4,481,077, and a variety of uses are described in U.S. Pat.Nos. 4,341,807 and 4,378,381, et al, hereby incorporated by reference.

In one embodiment of the present invention, the moisture content in theblended or mixed granular filtration media with nanofibers is in therange of 3% to 70% by weight; preferably, in a range of 5 to 65%; morepreferably, in a range of 5% to 60%, in the range of 10% to 60%, in therange of 20% to 50%, in the range of 30% to 40%, or in the range of 35%to 45%.

In another embodiment, further provides the method of preparing agranular filtration media mixture comprising the steps of:

-   -   a. Dispersing the nanofiber in a solvent composition to prepare        a nanofiber dispersion. The dry nanofiber or wet cake nanofiber        is added into and further dispersed by vigorously agitation or        mixing, such as by homogenizer in a solvent composition for a        period of time from 2-60 minutes. A solvent composition includes        but not limited to water, aqueous solution, organic solvent, or        any combination of them with or without dispersant added first.        The concentration of nanofiber in the final dispersion is not        more than 10% in the dispersion, preferably, not more than 5%.    -   b. Adding the conventional granular filtration media into the        nanofiber dispersion and admix them together for a period of        time from 2-60 minutes. Then separate the blended granular media        by filtration. The final granular filtration media mixture        product could be used as it is or to be further dried to not        less than 90%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%,        30%, 25%, 20%, 15%, 10%, 5%, or 3% of moisture content.

In one embodiment of the present invention, provides a method of use ofthe granular filtration media mixture comprised of nanofibers to removecontaminants from water source (e.g. drinking water, industrial water,environmental water, recreational water) by contacting the water withthe granular filtration media mixture with or without combination ofother filtration media for the purpose of water purification.

The contaminants which can be removed by contact with the mixture mediaof the present invention, include without being limited to: particulateparticles, colloidal particles, fine particles, suspended particles,organic, residual halogen such as residual chlorine or residual bromine,selenium, arsenate, arsenite, fluoride, dichromate, manganese, tin,platinum, iron, cobalt, chromate, molybdate, selenite, senelate,uranium, vanadium, vanadate, ruthenium, antimony, molybdenum, tungsten,barium, cerium, lanthanum, zirconium, titanium, and or radium, zinc,copper, lead, mercury, cadmium, as well as natural organic matter (NOM),pesticide and herbicide residues, endocrine disruptors, pharmaceuticalresidues and organic compounds released through industrial discharges.The particles include without being limited to: particles of lead,copper, iron oxides, ironoxyhydroxide, silica, et al. The contaminatedwater source includes without being limited to: tap water from municipalsupplies or rural wells; municipal water treatment; recreational waterfrom a pool or spa; environmental water; industrial process water;industrial waste water; municipal waste water; agriculture irrigationwater. The treated water can be used for drinking, industrial process,agriculture application or waste water discharge. The preferred watertreatment application for use of a granular filtration media mixturecomprising a granular filtration media and nanofibers is point-of-use,point-of-entry and municipal water treatment for drinking waterpurification.

In a preferred embodiment, the metal contaminants include without beinglimited to zinc, copper, lead, mercury, cadmium, iron, cobalt, chromate,dichromate, manganese, tin, etc.

The contaminant particles from the water source include without beinglimited to, particulate particles, colloidal particles, fine particles,suspended particles, which widely exist in the contaminated water. Thosecontaminant particles could come from:

-   -   Detached soil, mineral, or contaminant particles in water        source.    -   Solutes undergoing geochemical precipitation due to changes in        redox conditions from mixing with injected or percolated surface        water.    -   Emulsions of fine droplets from free phase hydrocarbons in the        water.    -   Agglomerations forming micelles seeded by macromolecules such as        humic acids in the water.    -   Colloids introduced directly into the groundwater from landfills        or other surface sources.    -   For example, on a mass basis, the colloid concentrations in a        groundwater can range from 1 to 75 mg/L.

More preferably, the contaminant particles from a water source includewithout being limited to, iron oxides, iron oxide hydroxides, silica,lead, copper, etc.

In a most preferred embodiment of the present invention, a particulateparticles of heavy metal contaminant in water is lead which exists in avariety of inorganic forms in water. The most common forms of inorganicparticulate lead in water are lead carbonate (PbCO3), lead hydroxide[Pb(OH)2], and lead hydroxycarbonate [Pb3(OH)2(CO3)2]. Ion forms of leadthat may exist in water are Pb2+, PbOH+, and Pb(OH)3−. Lead ion maycomplex with natural organic matter (NOM) in water, such as humic acid,tannins, and fulvic acids. Furthermore, the lead is subject toadsorption onto particles in water and ion exchange with clay particles.As the pH within the range of pH of drinking water and carbonateconcentration in the water increase, the solubility of lead decreases,and further generated insoluble particulate lead.

More specifically, according to NSF/ANSI 53 protocol (2011a publishedApril 2012), which defined a protocol to determine the lead in thewater, the first portion representing the total lead [Pbt] sample (frominfluent or effluent) must be transferred immediately to a sample bottlethat contains adequate nitric acid to lower the pH of the sample tobelow 2.0 for the total lead determination. A second portion of thesample (from the same influent or effluent) collected must beimmediately passed through a 0.1 micron absolute filter and collectedinto a sample bottle that contains adequate nitric acid to lower the pHof the sample below 2.0. This sample is collected to determine the 0.1micron filtrate lead, [fPb0.1]. A third portion of the sample (from thesame influent or effluent) must be immediately passed through a 1.2micron absolute filter and collected into a sample bottle that containsadequate nitric acid to lower the pH of the sample below 2.0. Thissample is 1.2 micron filtrate lead sample, [fPb1.2].

The total particulate lead [Pbtp] is calculated as follows:

[PBTP]=[PBT]−[FPB0.1].

The percent of total particulate lead % [Pbtp] is calculated as follows:

% [PBTP]={[PBT]−[FPB0.11]}/[PBT]X100.

The fine particulate lead [Pbf] is defined as the portion of totalparticulate lead between 0.1 and 1.2 micron in size (fine), andcalculated as follows:

[PBF]=[FPB1.2]−[FPB0.1].

The percent of fine particulate lead % [Pbf] is calculated as follows:

% [PBF]={[PBF]/[PBTP]}X100.

The standard NSF 53 pH 8.5 particulate lead testing water is alsospecifically defined in the NSF/ANSI 53 protocol (2011a published April2012). Illustrative source water specifications according to theNSF/ANSI 53 protocols (2011a published April 2012) are described asfollows: hardness of 90-110 mg/L, alkalinity of 90-110 mg/L, totalchlorine of 0.25-0.75 mg/L, pH of 8.3-8.6. The testing water mustcontain the overall average of 150±15 ppb of total lead, and the totalparticulate lead (lead % [Pbtp]) in the testing water is allowed onoverall average of 20-40%, and the testing water must also contain theoverall average of more than 20% of % [Pbf] which is the portion oftotal particulate lead that is between 0.1 and 1.2 microns in size (fineparticle size).

Referring to FIG. 1, a filter 100 in accordance with some embodiments isschematically illustrated. The filter 100 includes a first upper chamber106 and a second lower chamber 110 separated by a screen 108. The screen108 is optional in some embodiments. As depicted by the arrows, thewater to be filtered can flow from the top of the filter and exit fromthe bottom of the filter. The filter 100 can for example, be connectedto the entry of a collection jug, wherein the unfiltered water can bepoured over the top of the filter 100, so that water flows under theforce of gravity through the filter 100 into the jug.

In some embodiments, the upper chamber 106 has a first media layercomprising of a mixture of granular filtration media 104 and nanofibers102. The nanofibers 102 can be placed in the interstitial spaces betweenthe individual granular particles 104. In other embodiments, the lowerchamber 110 can include the mixture of granular filtration media 106 andnanofibers 102. In some embodiments, the filter 100 can include a singlechamber having the mixture of granular filtration media 104 andnanofibers 102. As can be seen in FIG. 1, the nanofibers 102 partiallyfill the voids that are created between the granular filtration media104. For example, the void fraction of the granular filtration mediaalone without nanofibers can be in the range of 0.02 (2%) to 0.07 (70%).However, when the nanofibers are combined with the granular filtrationmedia, the void fraction is reduced to the range of 0.01 (1%) to 0.65(65%). In an embodiment, the void fraction is reduced to the range of0.02 (2%) to 0.5 (50%). In another embodiment, the void fraction isreduced to the range of 0.30 (30%) to 0.4 (40%). An advantage of thenanofibers is the ability to retain certain fine particles and colloidalparticles that would otherwise pass unfiltered due to the void space ofthe granular filtration media alone. The nanofibers also do notsignificantly decrease the flow through the filter. Accordingly, anadequate flow of water can be induced solely through the force ofgravity or through low pressure applications.

In some embodiments, the lower chamber 110 is filled with a secondgranular filtration media and the second granular filtration media issupported on a second screen 112.

The granular filtration media 104 of the upper chamber 106 can include,but, is not limited to any of the granular filtration media describedherein and having the properties as also described herein. Thenanofibers 102 can include any of the nanofibers described herein andhaving the properties as also described herein. The second filtrationmedia of the second lower chamber 110 can include, but, is not limitedto zeolites, ion exchange resin, and silica.

Referring to FIG. 2, another filter 200 in accordance with someembodiments is illustrated. As can be seen in FIG. 2, the filter 200includes a single chamber 206 with a single layer of filtration mediasupported by the screen 212. In the embodiments of FIG. 2, the screenseparation the first and second filtration media has been removed.

As with the embodiments of FIG. 1, the embodiments of FIG. 2 alsoinclude a mixture of granular filtration media 204 and nanofibers 202.In addition, the filtration media can include additional filtrationmedia 210 corresponding to the filtration media 110 of the secondchamber in FIG. 1. That is, additional filtration media, such aszeolites, ion exchange resin, and silica, can be combined with thegranular filtration media 204 and nanofibers 202.

The granular filtration media 204 can include, but, is not limited toany of the granular filtration media described herein and having theproperties as also described herein. The nanofibers 202 can include anyof the nanofibers described herein and having the properties as alsodescribed herein. The filtration media 210 corresponds to the filtrationmedia of the second lower chamber 110 shown in FIG. 1. That is, thefiltration media 210 can include, but, is not limited to zeolites, ionexchange resin, and silica.

In the embodiments of FIG. 2, the nanofibers 202 can reduce the porosityand void space created by the granular filtration media and the secondmedia 210. For example, the void fraction of the granular filtrationmedia alone without nanofibers can be in the range of 0.02 (2%) to 0.07(70%). However, when the nanofibers are combined with the granularfiltration media, the void fraction is reduced to the range of 0.01 (1%)to 0.65 (65%). In an embodiment, the void fraction is reduced to therange of 0.02 (2%) to 0.5 (50%). In another embodiment, the voidfraction is reduced to the range of 0.30 (30%) to 0.4 (40%). Anadvantage of the nanofibers is the ability to retain certain fineparticles and colloidal particles that would otherwise pass unfiltereddue to the void space of the granular filtration media alone. Thenanofibers also do not significantly decrease the flow through thefilter. Accordingly, an adequate flow of water can be induced solelythrough the force of gravity or through low pressure applications.

In one embodiment of the present invention, provides a water filtercomprising of a mixture media of granular filtration media andnanofibers alone described as above, or any combination with othergranular filtration media component which could be porous and ornonporous, dry or moisture-containing, having the particle size oraverage particle size in the range of 100-2000 microns. In a preferredembodiment, the particle size or average particle size distribution ofother granular filtration media is in the range of 250-2500 microns,more preferably, the particle size or average particle size distributionin the range of 300-1000 microns. Examples of other filtration mediaincludes without being limited to, activated carbon particles, granularactivated carbon (GAC), silica gel, sand, fractured anthracite coal, ionexchange resin beads, granular hybrid of activated carbon with metaloxides, functionalized granular activated carbon, ion exchanger-basedhybrid particles such as iron oxide hydroxide hybrid ion exchange hybriddescribed in U.S. Pat. Nos. 7,504,036; 7,291,578; 7,708,892, polymericadsorbent resins such as Amberlite™ XAD type of polymeric adsorbents,activated alumina, zeolites, clay minerals, synthetic molecular sieves,KDF process filtration media (Cu—Zn formulations), aluminosilicates,titanates, bone char, ceramic, diatomaceous earth (DE) or metaloxide-hydroxide impregnated DE (traded name-NXT-2 media furtherdescribed in U.S. Pat. No. 8,110,526), or any combinations of thereof.In a preferred embodiment, the granular filtration media is selectedfrom ion exchange resin particles; zeolites; activated carbon particles(in with or without functionalization); synthetic molecular sieveparticles; diatomaceous earth; silica; clay.

A water filter of the present invention can be prepared by filling amixture comprising the granular filtration media and nanofibers into afilter cartridge chamber or a filter bed or a filtration vessel, with orwithout screen, one layer or multiple layers with or without combinationof other filtration media. The water contaminants can be removed byallowing a contaminated water to flow through the filter cartridge orthe filter bed to remove the contaminants for the purpose of waterpurification. More specifically, the water filter can be designed orprovided as a gravity-fed or a low pressure-fed filtration cartridge,filtration bed, and or filtration column to remove the contaminants fromwater for water purification application.

Specifically, the water filter of the present invention can be used in atap water from municipal supplies or rural wells; point-of-use;point-of-entry; municipal water treatment; recreational water from apool or spa; environmental water; industrial process water; industrialwaste water; municipal waste water and agriculture irrigation water toremove contaminants, including without being limited to: particulateparticles, colloidal particles, fine particles, suspended particles,organic, residual halogen, selenium, arsenate, arsenite, fluoride,dichromate, manganese, tin, platinum, iron, cobalt, chromate, molybdate,selenite, senelate, uranium, vanadium, vanadate, ruthenium, antimony,molybdenum, tungsten, barium, cerium, lanthanum, zirconium, titanium,and or radium, zinc, copper, lead, mercury, cadmium, as well as naturalorganic matter (NOM), pesticide and herbicide residues, endocrinedisruptors, pharmaceutical residues and organic compounds releasedthrough industrial discharges.

In one preferred embodiment, the invention provides a water purificationfilter comprised of the first layer media by admixing two differentgranular filtration media with nanofibers and a second layer of granularfiltration media, with or without a screen to separate the first mediaand the second media, or just a blend the first and second media layers.Preferably, the first filtration media layer provided by this inventionis selected from any mixture combinations of nanofibers admixed with anycombinations of activated carbon particles (including functionalizedand/or treated), zeolite, ion exchange resin, or silica, etc. The secondfiltration media layer is selected from ion exchange resin, zeolite. Thescreen to separate the first media and the second media has mesh sizemore than 70. This filter can be further designed, produced or used in agravity flow and or a low pressure flow cartridge, to remove chemicalcontaminants including without being limited to, organic matters,copper, zinc, mercury, cadmium, lead, residual halogen such as residualchlorine or residual bromine in the drinking water source. This filtercan be used in the point-of-use and point-of-entry, some examplesinclude without being limited to, pour-through carafes, water coolersand refrigerator water tanks, and pitchers, etc.

In one aspect, the inventions described herein can be used to removeparticular and soluble lead from drinking water using a gravity fed orlow pressure device. In an embodiment, the total lead amount in thepurified water is below 10 ppb for 300 L of water.

As there is a dynamic equilibrium between soluble and particulate leadspecies, the particulate lead species shifts back and forth to solublelead. This equilibrium is affected by the concentration of soluble leadin solution and also by the pH of the water. Depending on the size,soluble lead can be called colloidal.

In an aspect, the present invention describes a granular filtrationmedia mixture of granular filtration media and nanofibers which has theadvantage of trapping the smaller sized lead into the pores of thegranular filtration media and trapping the larger sized lead particlesin the granular filtration media mixture fibril mesh. In an embodiment,the smaller lead is also trapped in the mesh.

In an aspect, the inventions described herein can utilize thisequilibrium to remove particulates and colloidal lead from the water.Using a granular filtration media mixture, particulate leads areadsorbed in the granular filtration media mixture until they becomesoluble. At that point, a third media, such as for example, ion exchangemedia (“IXR”) can exchange the soluble lead for sodium or hydrogen.Granular filtration media mixture forms a net or matrix or mesh thatretains or binds the colloidal and particulate lead. In an aspect theNFC can be, for example, lyocell fiber (from wood pulp), 3-6 mm length,degree of fibrillation of 40-300 mL, and average diameter of 0.3microns. Other forms of NFC can also be used. The GAC mesh size can beeither one single mesh (i.e., 18, 20, 25, or 30) or a range (e.g 8X50,12X40, or 20X50) with 16X50 being the preferred. The fibrilnet/matrix/mesh formed during the manufacture of the granular filtrationmedia mixture is, among other things, related to the amount of moisture(“% MC”) present in the final composite. The higher the % MC the higherthe lead removal by the net, but the slower the flow rate of the wateris passing through it. The ideal % MC is in the range of about 40 andabout 70%. The % MC can also be in the range of about 45% MC to about65% MC; from about 50% MC to about 60% MC; or about 65% MC. An IXRparticle size of about 500 to 800 microns; about 550 to 750 microns;about 600 to 700 microns; about 650 to 900 microns; about 650 to 790microns; or about 730 to 780 microns; can be used. In an embodiment thegranular filtration media mixture composite is very uniform incomposition or is not uniform in composition.

In an embodiment, the particulate lead is trapped in the fibrilnet/matrix/mesh formed during the manufacture of the granular filtrationmedia mixture converts to soluble lead and is then exchanged by the IXRto sodium and hydrogen. In another embodiment, a potassium buffer may beadvantageous in the lead removal or reduction.

In another aspect, the nanofiber of the mixture is between about 0.05 toabout 0.8 g nanofiber per 130 mL of the granular filtration mediamixture. In an embodiment the lower end of the range is about 0.06 toabout 0.3 and the upper end of the range is about 0.31 to about 5.0 gnanofiber per 130 mL of the granular filtration media mixture

In an embodiment, the amount of lead in the resulting filtered water isbelow about 50 ppb, below about 47 ppb, below about 45 ppb, below about42 ppb, below about 40 ppb; below about 37 ppb; below about 35 ppb;below about 32 ppb; below about 30 ppb; below about 27 ppb; below about25 ppb; below about 22 ppb; below about 20 ppb; below about 19 ppb;below about 18 ppb; below about 17 ppb; below about 16 ppb; below about15 ppb; below about 14 ppb; below about 13 ppb; below about 12 ppb;below about 11 ppb; below about 10 ppb, below about 9 ppb, below about 8ppb, below about 7 ppb, below about 6 ppb, below about 5 ppb, belowabout 4 ppb, below about 3 ppb, below about 2 ppb, or below about 1 ppb.

While illustrative embodiments have been illustrated and described, itwill be appreciated that various changes can be made therein withoutdeparting from the spirit and scope of the invention.

EXAMPLES Example 1 Particulate Lead Removal Testing of Mixture of GACand NFC

1) Material and reagents:

-   -   Nanofibrillated cellulose (NFC) wet cake supplied by Engineered        Fiber Technologies, LLC.    -   Granular activated carbon (GAC): 12×40 mesh acid washed,        supplied by Filtrex Technology, India.    -   Lead (II) nitrate: Sigma-Aldrich, ACS reagent    -   Sodium Bicarbonate: VWR, ACS reagent    -   Magnesium Sulfate Heptahydrate: Sigma-Alich, ACS reagent    -   Chloride Dihydrate: EMD Chemicals, >99.0% 1.0 N Sodium Hydroxide        solution, lab made.    -   Deionized water (DI): resistivity >1.0 MΩ-cm (conductivity <1        μS/cm) VWR Filter paper 417 (pore size 40 μm), supplied by VWR.    -   Pall Arcodisc 32 mm syringe filter with 0.1 μm Super membrane,        Pall Corporation    -   Plastic column: 7.5 cm diameter.

2) Stock solution for particulate lead solution preparation

The following stock solutions were prepared with ultrapure wateraccording to the NSF/ANSI 53 protocol (2011a published April 2012).Calcium Chloride solution (38 g/L); Magnesium sulfate solution (32 g/L);Sodium bicarbonate solution (63 g/L); Soluble lead stock solution (3.6g/L with 4 mL of 1:1 diluted Nitric Acid); Insoluble lead stock solution(1.6 g/L, pH<6.5).

3) The Preparation of standard NSF53 pH 8.5 particulate lead testingwater

The standard NSF 53 pH 8.5 particulate lead testing water is prepared asdefined in the NAF/ANSI 53 protocol (2011a published April 2012).Illustrative source water specifications according to the NSF/ANSI 53protocols (2011a published April 2012) are as follows: hardness of90-110 mg/L, alkalinity of 90-110 mg/L, total chlorine of 0.25-0.75mg/L, pH of 8.3-8.6.

The testing water contains the average 150±15 ppb of total lead with20-40% of total lead being particulate lead which is greater than 0.1 μmaccording to NSF/ANSI 53 protocol (2011a published April 2012).

The procedure to prepare 5 L of the testing water is described as below:

-   -   1) Into 5 L plastic container, 5 L of DI water was added and        stirred at moderate speed.    -   2) 13.2 mL each of magnesium sulfate solution, calcium chloride        solution and sodium bicarbonate solution was added sequentially        into the 5 L solution under moderate speed mixing.    -   3) 55 μL of commercial bleach was added to the solution.    -   4) The pH of the solution was adjusted to pH 8.5 (pH 8.3-pH8.6)        with 1.0N sodium hydroxide solution under mixing.    -   5) Total available chlorine (TAC) was checked in the range of        0.25-0.75 mg/L TAC using HACH Spectrophotometer.    -   6) 264 μL of soluble lead stock solution was added to the        solution under mixing.    -   7) 13.2 mL of the solution was transferred into a 25 mL plastic        container.    -   8) The solution in the 25 mL plastic container was mixed        rapidly, followed by adding 264 μL of insoluble lead stock        solution into the 25 mL plastic container, continue rapid mixing        for 60 second, and then immediately transferred the solution        into the 5 L plastic container under moderate mixing.    -   9) The 5 L of particulate lead testing water in 5 L plastic        container was used as fresh immediately for Lead removal        testing.

4) The preparation of particulate lead testing water formulation

The additional particulate lead can be added into the above standard NSF53 pH 8.5 particulate lead testing water to further increase theparticulate lead concentration by following the same procedure as theabove that the particulate lead was added to the initial test water. Thefinal particulate lead testing water is used as fresh for lead removaltesting.

5) Preparation of mixture of GAC and NFC

Into 150 mL of Deionized water, 1.0 g of NFC wet cake (0.2 g dry weightof NFC) was added while vigorously agitating, and then maintained thevigorous mixing for another 30 minutes, the NFC-water dispersion wasobtained. Followed by adding 50 grams of GAC, and maintained themoderate agitating for another 10 minutes to blend the GAC and NFC inthe water. The final mixture of GAC and NFC was obtained by filtrationand further was tested as the following column testing. Another blankGAC sample was made by adding GAC into 150 mL of deionized water andfollowed by the moderate mixing for 10 minutes, and the final blank GACsample was obtained by filtration, and further was tested as followingcolumn testing.

6) The column set up for the column testing of particulate lead removal.

Into a plastic column with 7.5 cm diameter, a filter paper with 40micron pore size was placed at the bottom of the column to preventparticles or NFC from escaping from the column and further contaminatingthe effluent. Followed by placing the whole mixture of GAC and NFCprepared as above, then the same filter paper was also placed on the topof the media in the plastic column. The blank GAC testing column was setup as the same procedure only replacing the mixture media of GAC and NFCby blank GAC prepared as the above prepared.

7) The column testing of particulate lead removal

According to NSF/ANSI 53 protocol (2011a published April 2012), thefirst portion representing the total lead [Pbt] sample (from influent oreffluent) shall be transferred immediately to a non-glass sample bottlethat contains adequate nitric acid to lower the pH of the sample tobelow 2.0. A second portion of the sample (from the same influent oreffluent) collected from the non-glass sampling vessel shall beimmediately passed through a 0.1 micron absolute filter and collectedinto a non-glass sample bottle that contains adequate nitric acid tolower the pH of the sample below 2.0. This sample is the 0.1 micronfiltrate lead sample [fPb0.1].

The total particulate lead [Pbtp] shall be calculated as follows:

[Pbtp]=[Pbt]−[fPb0.1].

The particulate lead testing water prepared as above item 3. The initialinfluent for the 1st liter of column testing was sampled first for thetotal lead and total particulate lead analysis in a plastic containerwhich had nitric acid as preservative before the column testing wasstarted, immediately followed by gravity-fed the 1st liter of influentparticulate lead testing water respectively into the columns filled bymixture of GAC and NFC, or blank GAC, and then allowed the testing waterflow through the columns by gravity-fed. The whole effluent samples werecollected in a 1 L of plastic container respectively from each column,and further prepared for samples for total lead and total particulatelead analysis.

After the 1st liter of lead testing water sample completely passedthrough the columns, instantly followed by repeating the same procedurefor letting the 2nd liter of testing water flow through the columns.

The lead determination was conducted by EPA 200.8 method, which wasentitled “Determination of Trace Elements in waters and wastes byinductively coupled plasma-mass spectrometry”.

The following table 1 listed the particulate lead removal results frommixture of GAC and NC.

TABLE 1 The particulate lead removal testing of mixture of GAC and NFCMixture of Testing Blank GAC GAC and NFC water Items 1^(st) L 2^(nd) LAverage 1^(st) L 2^(nd) L Average Influent Total Pb (ppb) 272 281 276.5272 281 276.5 0.1 micron 171 164 — 171 164 — filtrate Pb (ppb) Totalparticulate 101 117 109 101 117 109 Pb (ppb) pH 8.58 8.58 8.58 8.58 8.588.58 Effluent Total Pb (ppb) 123 141 132 100 117 108.5 0.1 micron 57.864.9 — 57.7 64.2 — filtrate Pb (ppb) Total particulate 65.2 76.1 70.742.3 52.8 47.6 Pb (ppb) Total particulate 35.4 35.0 35.2 58.1 54.9 56.5lead removal % pH 8.31 8.31 8.31 8.31 8.23 8.27 Flow rate (ml/min) 467476 471.5 251 248 249.5

The results from table 1 clearly demonstrated that the mixture of GACand NFC showed much higher total particulate lead removal efficacy thanthe blank GAC.

Example 2: Particulate Lead Removal Testing of Mixture of Zeolite andNFC

In this example, the raw material zeolite was supplied by ZeotechCorporation under the trade name Zeobrite which was a granular naturalzeolite. The mixture of zeolite and NFC was prepared to follow the samemethod as the above example 1 by only replacing the GAC with zeolite.The blank zeolite was prepared by adding zeolite into 150 mL ofdeionized water and followed by the moderate mixing for 10 minutes, andthe final blank zeolite sample was obtained by filtration, and furtherwas tested by the column testing.

All the particulate lead testing water samples were prepared and used asfresh, all the column testing set up and testing procedure were repeatedas the example 1.

The following table 2 listed the particulate lead removal results fromthe mixture of zeolite and NFC.

TABLE 2 The particulate lead removal testing of mixture of zeolite andNFC Mixture of Testing Blank zeolite zeolite and NFC water Items 1^(st)L 2^(nd) L Average 1^(st) L 2^(nd) L Average Influent Total Pb (ppb) 184184 184 184 184 184 0.1 micron 125 125 — 125 125 — filtrate Pb (ppb)Total particulate 59 59 59 59 59 59 Pb (ppb) pH 8.56 8.56 8.56 8.56 8.568.56 Effluent Total Pb (ppb) 45.8 61.3 53.6 43.7 56.2 50 0.1 micron 34.643 — 39.9 47.9 — filtrate Pb (ppb) Total particulate 11.2 18.3 14.8 3.88.3 6.1 Pb (ppb) Total particulate 81.0 69.0 75.0 93.6 85.9 89.7 leadremoval % pH 8.34 8.39 8.37 8.37 8.38 8.38

The results from table 2 clearly demonstrated that the mixture ofzeolite and NFC showed much higher particulate lead removal efficacythan the blank zeolite.

Example 3: Particulate lead removal testing of mixture of ion exchangeresin and NFC

In this example, the raw material ion exchange resin (IER) beadsAmberlyst 15 (strong acidic cationic exchanger) was supplied by DowChemical Co. The Amberlyst 15 was first converted from proton type intosodium type by mixing it within 1 N of sodium hydroxide solution.

Wood cellulose fine powder Fiber Clear (FC), was supplied by FiberClear, Inc. The media mixture of IER and NFC, and the mixture media ofIER and Fiber Clear (FC) was respectively prepared by repeating theprocedure of item 5 of the example 1 by only respectively replacing GACby IER or replacing NFC by FC.

The blank IER was prepared by respectively adding IER into 150 mL ofdeionized water and followed by the moderate mixing for 10 minutes, andthe final blank IER was obtained by filtration, and further was testedby the column testing.

All the particulate lead testing water samples were prepared and used asfresh, all the column testing set up and procedure were repeated as theexample 1.

The following table 3 listed the particulate lead removal results fromthe mixture of IER and NFC, and the mixture of IER and Fiber Clear.

TABLE 3 The particulate lead removal testing of mixture of IER and NFCMixture of Mixture of Testing water IER IER and NFC IER and Fiber ClearItem 1^(st) L 2^(nd) L Average 1^(st) L 2^(nd) L Average 1^(st) L 2^(nd)L Average Influent Total Pb (ppb) 216 216 216 216 216 216 216 216 2160.1 micron 104 104 104 104 104 104 104 104 104 filtrate Pb (ppb) Totalparticulate 112 112 112 112 112 112 112 112 112 Pb (ppb) pH 8.52 8.528.52 8.52 8.52 8.52 8.52 8.52 8.52 Effluent Total Pb (ppb) 74.8 95.585.2 12.9 23.4 18.15 61.3 82.2 71.75 0.1 micron 18.9 22.8 20.9 7.8 14.711.25 16.1 21.1 18.6 filtrate Pb (ppb) Total particulate 55.9 72.7 64.35.1 8.7 6.9 45.2 61.1 53.2 Pb (ppb) Particulate 50.1 35.1 42.6 95.4 92.293.8 59.6 45.4 52.5 Pb removal % pH 8.58 8.58 8.58 8.57 8.57 8.57 8.588.57 8.58 Flow rate ml/min 288 297 292.5 253 258 255.5 258 262 260

The results from table 3 clearly demonstrated that the mixture of IERand NFC showed much higher particulate lead removal percentage than theblank IER or the comparison with the mixture of IER and cellulose finepowder supplied by Fiber Clear.

Example 4: Particulate Lead Removal Testing of Top Layer Wet-Laid by NFC

In this example, the raw material GAC were used as the same as theexample 1. The raw material cellulose fine powder supplied by FiberClear (FC) was used the same as the example 3.

The columns preparation of the mixture media of GAC and NFC, and themixture media of GAC and Fiber Clear were also followed by repeating theprocedure of example 1.

The columns of top layer wet-laid by NFC or Fiber Clear (FC) wereprepared by first preparing the 100 ml of NFC dispersion and 100 ml ofFiber Clear slurry by adding 0.2 g dry weight of NFC or 0.2 g dry weightof Fiber Clear into the 100 ml of deionized water, and followed byvigorously mixing for 30 minutes; then followed by respectively pouringthe dispersion of NFC or slurry of FC into the plastic columns whichwere first placed a 40 micron filter paper at the bottom and thenfurther filled with 50 grams of GAC. Finally another 40 microns filterpaper was respectively placed on the top of wet laid NFC or FC in thecolumns.

The particulate lead testing water was prepared as the same proceduresdescribed in the example 1.

All the sampling and the particulate lead removal column testing werefollowed the same procedure described in the example 1.

All the particulate lead testing water samples were prepared and used asfresh.

The following table 4 listed the particulate lead removal results fromthe GAC and top wet-laid columns by NFC and FC.

TABLE 4 The particulate lead removal testing of GAC and top wet-laidcolumns Top layer Top layer GAC wet-laid by NFC GAC wet-laid by FC GAC1^(st) L 2^(nd) L Average 1^(st) L 2^(nd) L Average 1^(st) L 2^(nd) LAverage Influent Total Pb (ppb) 234 225 229.5 234 225 229.5 234 225229.5 0.1 μm Filtered 171 118 — 171 118 — 171 118 — (ppb) Totalparticulate 63 107 85 63 107 85 63 107 85 Pb (ppb) pH 8.52 8.53 8.538.52 8.53 8.53 8.52 8.53 8.53 Effluent Total Pb (ppb) 93.3 87.4 90.481.6 75 78.3 94.3 89.2 91.8 0.1 μm Filtered 48.8 43.2 — 55.8 49.6 — 50.146.5 — (ppb) Total particulate 44.5 44.2 44.4 25.8 25.4 25.6 44.2 42.743.5 Pb (ppb) Total particulate 29.4 58.7 44.0 59.0 76.3 67.7 29.8 60.145.0 Pb removal (%) pH 8.25 8.13 8.19 8.18 8.15 8.17 8.15 8.19 8.17 FlowRate (mL/min) 305 301 303 283 336 309.5 395 392 393.5

The results clearly demonstrated that the top layer wet-laid by NFCshowed significantly lower total lead in the effluent, and significantlyhigher particulate lead removal % than the control GAC alone or the toplayer wet-laid by fine cellulose fiber supplied by Fiber Clear.

Example 5: Flow Rate Testing of Mixture Media in Brita Pitcher Chamber

Raw material,

In this example, nanofibrillated cellulose (NFC), and granular activecarbon (GAC), deionized water and VWR filter paper 417 used in theexample are the same as described by the example 1.

The Brita Slim Model (40 oz capacity) and Brita Pitcher Filter ModelOB03 were both purchased from Fred Meyer.

Testing Filter Sample Preparation

The mixture of GAC and nanofibrillated cellulose was prepared to followup the procedure described in the above-said example 1. Into 300 mL ofdeionized water, predetermined amount of nanofibrillated cellulose wasadded and further dispersed by high speed mixing for 30 minutes,followed by adding 37 grams of GAC, and continued the mixing for another10 minutes. The final mixture of GAC and nanofibrillated cellulose wasseparated by filtration and ready for use.

The Brita Pitcher Filter (Model # OB03) was cut on the top to provide anopening, followed by emptying the media of the filter housing. Into theempty housing of the filter, first 8 grams of GAC media was filled intothe bottom, followed by filling the mixture of 37 grams of GAC andnanofibrillated cellulose prepared as above.

Another blank filter was prepared by filling 45 grams of GAC into theempty Brita Pitcher Filter (Model #0B03) housing.

Flow Rate Measurement

Brita Pitcher Slim model was used for the flow rate measurement.The-above prepared Brita filter was placed into the Brita Pitcher, and 1L of deionized water was filled in the upper reservoir of pitcher. Thetime needed for the 1 L of water completely pass through the pitcherfilter was measured by 7 replicates.

Table 5 list the flow rate measurement results.

Total GAC (g) 45 45 45 45 45 45 45 Amount of NFC 0 0.18 0.54 0.63 0.720.81 0.90 (g, dry weight) % NFC in the mixture 0 0.48 1.43 1.67 1.912.14 2.37 of GAC and NFC Average flow rate 941 596 340 257 157 134 110(ml/min)

The results from the table 5 clearly demonstrated the flow rate of thegravity-fed pitcher filter cartridge is significantly determined by theamount of nanofibrillated cellulose in the mixture media of granularactive carbon and NFC. As the amount of NFC increases, the flow ratewill significantly decrease. The nanofibrillated cellulose could be usedas an effective component to adjust the flow rate in a gravity-fedfilter filled with a granular active carbon.

Example 6: SF53 pH 8.5 Lead Reduction Testing of Modified Brita PitcherFilter

1. Material and reagents

Nanofibrillated cellulose (NFC) wet cake supplied by Engineered FiberTechnologies, LLC.

GAC: Resin Tech AGC-50-CSAD, granule activated carbon supplied by ResinTech Inc.

Brita Pitcher Filter OB03: purchase from Fred Myer,

Brita Pitcher: purchased from Fred Myer.

Ion Exchange Resin (IER): Resin Tech WACG-HP, a weak acid ion exchangeresin, supplied by Resin Tech Inc., further pre-treated by soaking itinto the pH3.7 buffer, and followed by 3 cycles of rinsing in thedeionized water, and ready for the testing.

Lead (II) nitrate: Sigma-Aldrich, ACS reagent; Sodium Bicarbonate: VWR,ACS reagent; Magnesium Sulfate Heptahydrate: Sigma-Alich, ACS reagent;Calcium Chloridedihydrate:EMDChemicals 99.0%,

1.0 N Sodium Hydroxide solution, lab made; Deionized water (DI):resistivity >1.0 MΩ-cm (conductivity <1 μS/cm); VWR Filter paper 417(pore size 40 μm), supplied by VWR.

2. Preparation of the mixture media of GAC and nanofibrillated cellulose(NFC)

Into 100 ml of the deionized water, 0.14 g of dry weight of NFC wasadded, and further dispersed by high-speed mixing to provide a slurry.Into the slurry, 40 ml of GAC was added and further mixing for 15minutes, then the mixed media was separated by filtration. The wholemedia was ready for filling into the filter housing.

3. Preparation of the modified Brita Pitcher Filters

-   -   The Brita Pitcher Filter OB03 was cut to open the top of the        filter, and further empty it by removing all the media to obtain        an empty Brita Pitcher Filter housing. Into the empty housing,        90 ml of pre-treated Resin Tech WACG-HP was placed first,        followed by adding 40 ml of mixed media of GAC and NFC. Then the        filter opening was glued and ready for the NSF 53 pH 8.5 lead        reduction testing. Another control filter was prepared by only        replacing the 40 ml of mixed media of GAC and NFC by 40 ml of        GAC.

4. NSF 53 pH8.5 lead reduction testing of modified Brita Pitcher Filters

The detailed procedure of preparing NSF53 pH8.5 lead test water wasdescribed in the example 1.

-   -   After the modified Brita Pitcher Filters were inserted tightly        into the Brita Pitchers, 1 L of the test water was poured into        each Brita Pitcher container. The effluent was collected in the        Brita Pitcher. The first 1 L of water sample was collected after        two liters of test water was passed through the pitcher, then 1        L of effluent sample was collected in every 30 liters of testing        volume during the total testing capacity of 300 L, and the        sampling was respectively conducted at the pitcher testing        volume at 30 L, 60 L, 90 L, 120 L, 150 L, 180 L, 210 L, 240 L,        270 L or 300 L. The pH of influent and effluent, and the flow        rate of test water through the pitchers were measured. The lead        concentration of the collected influent and effluent water        samples were determined by EPA 200.8 protocol.

5. NSF 53 pH8.5 lead reduction testing results of modified Brita PitcherFilters

The following table 6 demonstrated the NSF 53 pH8.5 lead reductiontesting results of modified Brita Pitcher Filters. The filter filledwith the mixed media of GAC and NFC showed the average of 1.9 ppb totallead in the effluent vs the average of 27.7 ppb total lead in theeffluent of the control sample, the former 1.9 ppb of total lead is farbelow NSF 53 standard which sets up maximum 10.0 ppb. The originalcontrol filter failed in the NSF 53 standard testing, however, themodified Brita Pitcher Filter filled with the mixed media of GAC and NFCsuccessfully passed the NSF53 testing standard for pH8.5 lead reduction.

TABLE 6 NSF53 pH 8.5 lead reduction testing results of modified BritaPitcher Filters Filter liter 2 30 60 90 120 150 180 NFC − GAC + IER Flowrate ml/min 143 137 120 120 113 110 113 pH 5.96 5.78 5.98 6.21 6.46 6.456.56 Pb (ppb) 0 0.9 0 1.1 1.7 2.0 2.4 Control Flow rate ml/min 265 284292 305 311 310 306 GAC + IER pH 6.24 5.89 6.13 6.31 6.51 6.55 6.93 Pb(ppb) 18.8 27.7 22.9 25.6 25.2 30.4 30.6 Test water pH 8.52 8.59 8.588.48 8.55 8.54 8.57 lead (ppb) Total Pb (ppb) 145 166 150 154 159 157165 [Pb_(tp)] (ppb) 27 52 33 41 42 40 49 [Pb_(f)] (ppb) na 18 na Na nana 25 Test water % [Pb_(tp)] 18.6 31.3 22.0 26.6 26.4 25.5 29.7 %[Pb_(tp)] % [Pb_(f)] na 34.6 na Na na na 51.0 % [Pb_(f)] Filter liter210 240 270 300 Ave NFC − GAC + IER Flow rate ml/min 115 120 119 121 121pH 6.9 6.75 6.96 6.92 6.45 Pb (ppb) 3.1 3.8 2.8 3.4 1.9 Control Flowrate ml/min 303 296 297 279 295 GAC + IER pH 6.82 6.80 6.87 7.04 6.55 Pb(ppb) 30.7 38.1 26.9 28.2 27.7 Test water pH 8.58 8.54 8.58 8.56 8.55lead (ppb) Total Pb (ppb) 170 181 156 160 160 [Pb_(tp)] (ppb) 40 66 3939 42.5 [Pb_(f)] (ppb) na Na na 16 19.7 Test water % [Pb_(tp)] 23.5 36.525.0 24.4 26.3 % [Pb_(tp)] % [Pb_(f)] na Na na 41.0 42.2 % [Pb_(f)]

Example 7: NSF53 pH 6.5 Lead Reduction Testing of Modified Brita PitcherFilter

All the raw material and reagents used in this example are the same asdescribed in example 6. The procedure of preparation of the mixturemedia of GAC and nanofibrillated cellulose (NFC), and the procedure ofpreparation of the modified Brita Pitcher Filters are repeated asdescribed in example 6.

The procedure of preparation of test water is conducted according toNSF/ANSI 53 protocol (2011a published April 2012), the local tap waterwas used for the testing.

The lead stock solution was prepared by dissolving 0.0720 g of leadnitrate in 500 ml of deionized water with 10 drops of concentratednitric acid added.

After the modified Brita Pitcher Filters were installed tightly into theBrita Pitchers, 30 L of test water was prepared in 55 L of plasticcontainer, which was fed into the Brita Pitcher automatically using autocontinuous feeder. 1 L of the influent and effluent water samples werecollected when the total volume of effluent was reached to the followingsampling points: 2 L, 75 L, 150 L, 225 L, 270 L and 300 L. The pH andresidual lead from the collected effluent water samples were analyzed.The flow rate was also measured during the test water flowing throughthe filters. The lead concentration of the collected influent andeffluent water samples were determined by EPA 200.8 method.

The following table 7 demonstrates the NSF 53 pH6.5 lead reductiontesting results of modified Brita Pitcher Filter. The filter filled withthe mixed media of GAC and NFC shows the average of 3.5 ppb total leadin the effluent vs the average 143.8 ppb found in the influent. Theaverage of 3.5 ppb of lead found in the effluent is far below NSF 53standard which sets up maximum 10.0 ppb. Therefore, the modified Britapitcher filter can also efficiently reduce the lead in compliance withthe lead reduction claim.

TABLE 7 NSF 53 pH 6.5 lead reduction testing of modified Brita pitcherfilter Pb (150 ppb) 2 L 75 L 150 L 225 L 270 L 300 L Ave. Influent pH6.38 6.58 6.47 6.48 6.46 6.46 6.47 Effluent Flow (ml/min) 102.6 82.087.6 94.2 79.7 83.8 88.3 pH 6.29 6.08 6.62 6.07 5.83 5.96 6.14 Leadinfluent 143 146 154 148 145 127 143.8 (ppb) effluent 2.4 3.3 2.6 3.54.0 5.0 3.5

Example 8: Determining the Fiber Content Versus the Filter Flow Rate

In this example, the media mixture was prepared using granular activatedcarbon (GAC, OmniPure Filter Company), weak acid ion exchange resin(IER, ResinTech Inc.), and nanofibrillated cellulose (NFC, SchwarzwalderTextil-Werke). The amount of NFC was varied and ranged from 0.7% to 5.0%of the total media dry mass (see table 8). A dispersion of NFC indeionized water was created by combining the mass of NFC listed in thetable 8 with 100 mL of deionized water. A commercial blender with theblades reversed was used to create a uniform dispersion of NFC in water.This dispersion was added to IER (27.6 g dry mass) and GAC (13.3 g drymass). This combination was mixed well, vacuum filtered to dewater, andthen remixed to generate a uniformly mixed filter media.

Packed cartridges were prepared using Kirkland Signature Water FilterCartridges (Item 1276702). These cartridges were cut on the top toprovide an opening and the original media in the cartridges was removedand disposed of. The media mixture prepared above was gently packed intothe filter cartridge and the top of the filter cartridge was sealedusing hot-melt adhesive.

The filter cartridge containing the media mixture was installed into aBrita pitcher (Lake Model Item 9993333), and NSF/ANSI 53 pH 8.5 leadtest water was poured into the upper reservoir of the pitcher in 1 literincrements. After the water completely passed through the filter and theupper reservoir was empty, the lower reservoir was emptied and anadditional 1 liter of test water was added to the upper reservoir. Thisprocess was repeated for 50 liters. The time required to filter oneliter of water through the filter was timed using a stopwatch and thenconverted to a flow rate in units of mL/min. The results for 0.7%,0.25%, and 0.5% dry weight of NFC are reported in the Table 8 below.

TABLE 8 Filter flow rates with different amounts of NFC in filter mediaAmount of NFC per cartridge (g, dry mass) 0.3 1.1 2.2 % NFC in mediamixture (based on dry mass) 0.7 2.5 5.0 Volume Filtered (L) Flow Rate 1241 382 263 (mL/min) 5 152 201 93.5 10 119 110 96.8 20 81.9 96.0 61.8 3082.3 69.8 61.2 40 75.5 58.6 23.3 50 51.1 61.5 27.7

The above data show that a gravity flow water filter cartridge with agranular filtration media having 5% dry weight NFC has a slower flowrate compared to the same cartridge with 0.7% and 2.5% dry weight NFC.For gravity flow water filtration, less than 50 mL/min would beconsidered commercially unreasonable. Furthermore, the life of a gravityflow water filtration cartridge should be greater than about 30 liters,after which the flow rate of the cartridge with 5% NFC starts to slowconsiderably, requiring 35-45 minutes to filter one liter of water.

1. Granular filtration media, comprising: nanofibers; granular activatedcarbon; and granular ion exchange resin, wherein the nanofibers arecomprised in a mixture with more than one different granular particles,wherein the granular particles include at least granular activatedcarbon and granular ion exchange resin, and wherein the nanofibersinclude at least a polymeric nanofiber, and wherein the nanofiberscomprise less than 2.5% dry weight of the granular filtration media. 2.The granular filtration media of claim 1, wherein the granular particleshave an average particle size from 100 microns to 2,000 microns and thenanofibers have an average diameter from 5 nanometers to 2 microns. 3.The granular filtration media of claim 1, wherein the nanofiberscomprise less than 2% or less than 1% by dry weight of the granularfiltration media.
 4. The granular filtration media of claim 1, whereinthe granular filtration media has a moisture content of 3% to 70% byweight.
 5. The granular filtration media of claim 1, wherein the mixturefurther comprises granular particles selected from granular activatedalumina, granular diatomaceous earth, granular silica gel, granularzeolites, granular silicates, granular synthetic molecular sieves,granular mineral clay, granular aluminosilicates, granular titanates,granular bone char, granular KDF process media, granular iodated resins,granular ceramic, granular perlite, granular sand, granular hybrid ofion exchange resin with metal oxides, granular hybrid of activatedcarbon with metal oxides, functionalized granular activated carbon,polymeric adsorbent resins, or any combination thereof.
 6. The granularfiltration media of claim 1, wherein the polymeric nanofibers arenanofibrillated cellulose.
 7. A method of making the granular filtrationmedia of claim 1, comprising: dispersing the nanofibers in a solvent;adding the more than one different granular particles to the solvent;mixing the solvent with the nanofibers and the granular particles; andseparating the solvent to make the granular filtration media.
 8. Themethod of claim 7, further comprising drying the granular filtrationmedia.
 9. The method of claim 7, wherein the granular particles have anaverage particle size from 100 microns to 2,000 microns, and thenanofibers have an average diameter from 5 nanometers to 2 microns. 10.A method of removing impurities from a fluid, comprising: passing afluid comprising an impurity through a filter comprising the granularfiltration media of claim
 1. 11. The method of claim 10, wherein theimpurity is a halogen, heavy metal ion, organic compound, or a colloidalparticle.
 12. The method of claim 10, wherein the fluid is air or water.13. The method of claim 10, wherein the granular particles have anaverage particle size from 100 microns to 2,000 microns and thenanofibers have an average diameter from 5 nanometers to 2 microns. 14.The method of claim 10, wherein the impurity is lead.
 15. A method ofremoving impurities from a fluid, comprising: passing a fluid comprisingan impurity through a filter comprising the granular filtration media ofclaim 1, wherein the impurity is lead, copper, iron oxide, iron oxidehydroxide, silica, copper, mercury, cadmium, zinc, or any combinationthereof.
 16. A filter, comprising: chamber comprising the granularfiltration media of claim
 1. 17. A method of making a filtration system,comprising: installing a filter according to claim 16 in a gravity fedor low pressure filtration system, wherein the filtration system iscapable of removing a metal selected from the group consisting ofcopper, zinc, mercury, cadmium, and lead; and further wherein thefiltration system is capable of producing water in compliance with NSF42 and NSF 53 standards.